C# DateTime

Summary: in this tutorial, you will learn how to use the C# DateTime type to work with date and time values.

Creating C# DateTime objects

The DateTime is a value type that represents dates and times with values from January 1, 0001, 00:00:00 (midnight) to 11:59:59 PM, December 31 9999.

To create a DateTime object, you call its constructor and pass various date and time properties such as year, month, day, minute, hour, and second. For example:

using static System.Console;

var dt = new DateTime(2023, 5, 15, 7, 0, 0);
WriteLine(dt.ToString());Code language: C# (cs)

Output:

5/15/2023 7:00:00 AMCode language: C# (cs)

In this example, we create a DateTime object with the value 7:00:00 AM on May 15, 2023. The DateTime constructor has many constructor overloads.

For example, if you use only year, month, and day, the time will default to 12:00:00 AM:

using static System.Console;

var dt = new DateTime(2023, 5, 15);
WriteLine(dt.ToString());Code language: C# (cs)

Output:

5/15/2023 12:00:00 AMCode language: C# (cs)

Accessing C# DateTime properties

The DateTime object provides many useful properties that allow you to work with dates and times easily.

For example, you can access Year, Month, Day, Hour, Minute, and Second via the respective properties like this:

using static System.Console;

var dt = new DateTime(2023, 5, 15, 7, 0, 0);

WriteLine(dt.Year);
WriteLine(dt.Month);
WriteLine(dt.Day);
WriteLine(dt.Hour);
WriteLine(dt.Minute);
WriteLine(dt.Second);Code language: C# (cs)

Output:

2023
5
15
7
0
0Code language: C# (cs)

To get the current local time, you can use the DateTime.Now property. For example:

using static System.Console;

var dt = DateTime.Now;
WriteLine(dt.ToString());Code language: C# (cs)

It’ll output the current local time of the computer where you run the program.

Formatting C# DateTime values

The format of the date and time depends on many factors such as culture, international standards, and personal preference.

By default, the ToString() method of the DateTime object returns the string representation of a date and time value based on the current culture’s short-date and long-time pattern. For example:

using static System.Console;

var dt = new DateTime(2023, 5, 15, 7, 0, 0);

WriteLine(dt.ToString());Code language: C# (cs)

Output:

5/15/2023 7:00:00 AMCode language: C# (cs)

To ToString() method has many overloads that allow you to customize the representation of the date and time value.

For example, you can use the "d" and "D" format specifier to format a DateTime object using the short and long date pattern:

using static System.Console;

var dt = new DateTime(2023, 5, 15, 7, 0, 0);

WriteLine(dt.ToString("d")); // 5/15/2023
WriteLine(dt.ToString("D")); // Monday, May 15, 2023Code language: C# (cs)

Output:

5/15/2023
Monday, May 15, 2023Code language: C# (cs)

See the full standard date and time format string for reference

Performing DateTime Calculations

To return a new DateTime that adds a specified number of years, months, days, hours, minutes, and seconds to a value of a DateTime instance, you use the AddYears, AddMonths, AddDays, AddHours, AddMinutes, AddSeconds methods.

For example, the following program shows how to use the AddYears() method to add one year to a DateTime instance:

using static System.Console;

var dt = new DateTime(2023, 5, 15, 7, 0, 0);

// add one year
var dt2 = dt.AddYears(1);

WriteLine(dt2);Code language: C# (cs)

Output:

5/15/2024 7:00:00 AMCode language: C# (cs)

Because the Add* method returns a new instance of the DateTime, you can chain the Add* methods like this:

using static System.Console;

var dt = new DateTime(2023, 5, 15, 7, 0, 0);

// add 1 year, 2 months, 3 days, and 4 hours
var dt2 = dt.AddYears(1)
            .AddMonths(2)
            .AddDays(3)
            .AddHours(4);

WriteLine(dt2);Code language: C# (cs)

Output:

7/18/2024 11:00:00 AMCode language: C# (cs)

Notice that to subtract a specified number of years, months, days, hours, minutes, and seconds from a DateTime instance, you can use the Add* methods but use a negative value. For example:

using static System.Console;

var dt = new DateTime(2023, 5, 15, 7, 0, 0);

// subtract 1 year
var dt2 = dt.AddYears(-1);
WriteLine(dt2);Code language: C# (cs)

Output:

5/15/2022 7:00:00 AMCode language: C# (cs)

To calculate the time interval between two DateTime values, you can use the Subtract method. For example:

using static System.Console;

var dt1 = new DateTime(2023, 5, 15);
var dt2 = new DateTime(2022, 5, 15);


var interval = dt1.Subtract(dt2);
Console.WriteLine(interval.Days); // 365Code language: C# (cs)

In this example, we created two DateTime objects and use the Subtract() method to subtract the second DateTime object from the first one.

The return value of the Subtract() method is a time interval with the type TimeSpan. And finally, we display the number of days of the timespan on the console.

Summary

Use C# DateTime type to work with date and time values.

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